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masticatory process, the pars incisiva. The latter part, which is in most cases bounded off
from the dorsal insertion part by a slight contraction, is hent somewhat inwards, so that these
processes on the right and the left mandibles are situated about opposite and rather near to eacli
other, close to the mouth when these limbs are in a position of rest. The basale, which is rather
moveably united to the coxale, is always large andpowerftd, rather elongated and, like
thefollow-ing joints, strongly compressed from the sides. Proximo-ventrally it is drawn out into a very
powerful, broad, flattened masticatory process, which is cut ofE transversally distally and which
covers the pars incisiva on the coxale from outside almost like a shovel. The distal edge of this
masticatory process, which extends in most cases a short distance beyond the pars incisiva
on the coxale, is armed with a row of teeth. (As G. O. Sars pointed out in his work of 1887,
p. 74, the masticatory process on the basale seems to have the same function as the cutting
part on the mandible in many other Crustacea, while the pars incisiva on the coxale serves as
a sort of tuberculum molare to break up the food more finely. The latter process seems, however.
also to serve partly as a cutting organ.) For the relation of the position of the masticatory processes
on the coxale and basale to the atrium see G. \Y. MÜLLER, 1894, p. 48, pi. 1, fig. 19, pi. 40,
fig. 66. An epipodial appendage is developed fairly often ; it is moderately large
or else small, with only one or two bristles (it never funetions as a vibratory plate?); it is always
situated on the medial side of the basale, more or less proximally on the joint. The
exopo-d i t e is sometimes represented by a small, verruciform, unjointed process with or without
a single plumous bristle or else only by a single plumous bristle. It is situated dorso-distallv
on the basale, most frequently somewhat medially and somewhat proximally of the distal
boundary of this joint. It never seems to be quite absent. It does not contain the exits of any
glands (as in the Cypridiniformes) and never seems to serve as a vibratory piate. The e n
dopod i t c is always powerful and three-jointed, and forms a distinct, ventrally open knee together
with the protopodite.
Maxilla: — This varies rather slightly in this group. It is developed as a masticatory
organ, comparatively short and powerful and with a powerful musculature. It consists of a
three-jointed protopodite and a two-jointed end op odi te; the exopodite
and the epipodial appendage are always quite absent. When in a position of
rest this limb is situated as follows: The protopodite points forward and somewhat outward,
the first joint of the endopodite points rather decidedly downward, there is a bend chie fly
between the coxale and the basale; the first endopodite joint is twisted so that its greatest
breadth almost coincides with the longitudinal axis of the body; the end joint points
back-ward and downward or almost straight backward. Protopodite: This is comparatively
short and thick. Its three joints are always well defined and are moveably joined to one
another; the basale is moveably joined to the endopodite (both the coxale and the basale
as well as the first endopodite joint are moved by special muscles). The procoxale and
the coxale are comparatively large and powerful, the former being in most cases somewhat larger
and stronger than the latter; the basale is rather considerably smaller than the procoxale and
is moderately strong. The procoxale and the coxale are each armed with an endite. These
endites are rather large and powerful, immoveablv joined to these joints, flattened and armed
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